Extreme pressure lubricant



United States Patent EXTREME PRESSURE LUBRICANT No Drawing. Application October 20, 1953 Serial No. 387,324

2 Claims. (Cl. 252-.-46.6)

This invention relates to lubricants and methods of preparing the same, and more particularly to lubricant additives which impart extreme pressure characteristics to lubricants and methods for the preparation thereof.

It has long been known in theart of lubrication that the addition of sulfurized or sulfurized and phosphorized fatty material to lubricants will greatly increase the extreme pressure characteristics of the lubricant. For example, sulfurized fatty materials, such as lard oil and the like, have heretofore been used to increase the extreme pressure properties of mineral oil base and emulsion type metal working lubricants, such as cutting oils, and other lubricants which are subjected to high pressure during use. Likewise, sulfurized and phosphorized fatty materials have been used to increase the extreme pressure properties of lubricants, particularly automotive gear lubricants. Examples of the latter type of lubricants and their methods of preparation may be found in United States Patents 2,211,231 to Lawrence M. Henderson, issued August 13, 1940, and 2,211,306 to William A. Whittier et al., issued August 13, 1940. Although lubricants prepared and blended in accordance with the above and other patents relating to lubricants containing sulfurized or sulfurized and phosphorized fatty materials have satisfactory extreme pressure characteristics, they have been found deficient in certain other characteristics. One notable deficiency of the sulfurized or sulfurizedphosphorized fatty materials of the prior art has been their lack of universal solubility in mineral lubricating oils. been particularly vexing when attempts are made to incorporate extreme pressure additives in highviscosity index mineral oils such as Pennsylvania and Mid-Continent solvent refined oils. Inasmuch as extreme pressure additives of the type referred to above lack compatibility in high viscosity index oils, another serious drawback in the preparation of extreme pressure lubricants is the inability to obtain lubricants possessing both extreme pressure characteristics and high viscosity index characteristics. Difiiculties have also been experienced in the preparation of extreme pressure lubricants of satisfactory low temperature charcteristics. This problem is evidenced by the fact that the lubricants fail to remain fluid at low temperatures and thus do not provide proper lubrication at winter temperatures in temperate geographical zones.

It is, therefore, an object of the present invention to provide improved extreme pressure additives and lubricant blends containing these additives.

Another object of this invention is to provide extreme This lack of compatibility with mineral oils has 2,885,363 -Patnted May 5, 1959 2 pressure lubricant additives having improved solubility in mineral oil lubricants,

Another and further object of this invention is to provide extreme pressure lubricants having improved viscosity index characteristics.

Still another object of this invention is to provide extreme pressure lubricants having improved low temperature characteristics.

A further object of this invention is to provide extreme pressure lubricants having improved viscosity index characteristics and improved low temperature characteristics.

A still further object of this invention is to provide sulfurized and sulfurized-phosphorized lubricant additives having improved solubility in high viscosity index mineral oils.

Still another object of this invention is to provide improved methods of preparing extreme pressure lubricant additives having improved solubility in mineral oil lubricams and extreme pressure lubricants having improved viscosity index and low temperature characteristics.

Other and further objects of this invention will be apparent from the following detailed description of the invention.

In accordance with the present invention, it has been found that the presence of fatty esters containing polyethenoid linkages (also referred to as polyunsaturate glycerides) in fatty materials which are sulfurized or sulfurized and phosphorized to form extreme pressure lubricant additives adversely affects the solubility of such additives in mineral oils and the viscosity index characteristics of lubricants prepared therefrom. Although it is not intended to limit the scope of the invention by a theoretical explanation, it is believed that the polyun saturate glycerides enter into a chemical reaction either by polymerization or by combining with sulfur or sulfur and phosphorous to form oil-insoluble materials during the preparation of extreme pressure lubricant additives by sulfurization or sulfurization and phosphorization. Thus, it has been found that extreme pressure lubricant additives which are universally soluble in mineral oils and which form lubricants of improved viscosity index characteristics when blended with mineral oils can be prepared by counteracting the etfect of the polyunsaturate glyceride content of the fatty materials used in the preparation of sulfurized or sulfurized and phosphorized extreme pressure lubricant additives. The term counteract as used herein is meant to include reducing the polyunsaturate glyceride content of fatty materials prior to sulfurization or sulfurization and phosphorization as well as neutralizing or rendering inactive the polyunsaturate glycerides of fatty materials having normal polyunsaturate glyceride content. It has also been discovered in accordance with the present invention that the low temperature characteristics of lubricants prepared from sul furized or sulfurized and phosphorized fatty materials whose polyunsaturate glyceride content has been rendered inactive can be improved by counteracting the effect of the high melting point saturated fatty acid esters and, more particularly, the glyceryl esters of stearic, palrnitic and myristic acids present in the fatty material. By thus reducing or rendering inactive the glyceryl esters of stearic, palmitic and myristic acids, the low temperature characteristics of the lubricants of this invention can be improved without adversely aflecting the solubility and viscosity index characteristics of the lubricant.

Extreme pressure lubricant bases prepared according to the methods of sulfurizing and phosphorizing fatty oils described in United States Patents 2,211,231 and 2,211,- 306, supra, have been found to have limited solubility in lubricating mineral oils. Such extreme pressure lubricant bases are compatible with only limited types of mineral oil such as Gulf Coastal lubricating mineral oils and Mid-Continent conventionally refined lubricating mineral oils when the Mid-Continent conventionally refined oil is kept at a minimum. However, the extreme pressure lubricant bases prepared according to the methods described in the above-mentioned United States patents have poor compatibility with high viscosity index cent. The second extreme pressure lubricant base was prepared using lard oil of low polyunsaturate glyceride content (hereinafter referred to as LPU lard oil) in the range of l to 2 percent; the polyunsaturate glyceride content having been reduced by the Kellogg Solexol Process of propane solvent extraction. SAE 90 grade extreme pressure lubricant blends were prepared (1) using 18 percent of E.P. lubricant base, 1 percent dibenzyl disulfide as an additional extreme pressure agent and 81 percent of lubricating mineral oil and (2) using 9 percent of E.P. lubricant base, 1 percent of dibenzyl disulfide as an additional extreme pressure agent, and 90 percent of lubricating mineral oil. The solubility and viscosity index characteristics of extreme pressure lubricant blends containing the two diiferent E.P. lubricant bases are shown in Table I, below.

Table I Bllfnd Fatty oil used in E.P. base SAE 90 grade blend composition fill-day storage stability v.1.

L a u r t 207 1 3 Tail-5 i ii"ifi2i 1 at 0 12 0 p0 1 enzy Su 6 No separation of E P additive at room m 39 unsaturate glyceride con- 81'? wt. Gulf Coast mineral oil parts 160 tent. duh Coast bright stock) (51 parts 200 Gulf additive Ooast neutral). 18% wt. E.P. base 1% wt. dibenzyldlsulflde HeavyseparatlonofE.P.addltlveatreom temp. 107 2 do 81% wt. Mid-Continent solvent refined mineral within 48 hours. Heavy separation of E.P.

oil (36 parts 150 MOSR bright stock) parts additive at 32 F. within 48 hours. 170 MCSR neutral). 3 L a n r 27 1 97 i d i b i i"'ifi'i 8r 0 o 0 p0 No separation of F P additive at room t 11 unsaturate glyceride eon- 817 wt. Mid-Continent solvent refined Oil (37 tent. piarts 15o MGSR bright stock) 44 parts 110 separatmn at MCSR neutral). 332%? l ases Lard oil of 12 to 20% poly- Fmy u e 4 1.357 vis. index improve! (Acryloid 150) l glyceride 88.65 71, mixed blend G.C. and MOSR. oil 43 86 parts 160 Gulf Coast bright stock) (45.65 parts MCSR neutral). i ii -1i" i arih'i 1 enzy Su 9 Heav se aratlonolEP addltlv t t 112 5 do 90 wt. Mid-Continent solvent refined oil y p ea room 150 MCSR bright stack) (40 parts 170 Heavy separation of E.P. additive at 32 F.

CSR neutral). 9%, wttz. basegflifigun- 1 w enzy isu e..-- 6 Lard oil at 2'7 max. polyuna v N0 separation of E.P. additive at room temp. 110

saturate glyizeride content. gi gigg g gg gfififi g gggg ag ig gg N 0 separation of E.P. additive at 32 F.

CSR neutral).

mineral oils of the Pennsylvania and Mid-Continent solvent refined types.

It has been discovered that extreme pressure lubricant bases which are universally soluble in all types of lubricating mineral oils, including Pennsylvania, Mid-Continent solvent refined, Mid-Continent conventionally refined and Gulf Coastal mineral lubricating oils, can be prepared by employing a fatty material having a reduced polyunsaturate glyceride content in the preparation of the lubricant base. The polyunsaturate glyceride content of the fatty material is preferably reduced to a maximum of 6 percent for best results. Such reduction of polyunsaturate glyceride content of the fatty material can be brought about by treating the fatty material in accordance with the Kellogg Solexol process of propane solvent extraction or any other suitable method for the reduction of the polyunsaturate glyceride content of fatty materials.

The following example illustrates the advantages which are obtained by employing a material low in polyunsaturate glycerides as a fatty material in the preparation of sulfurized-phosphorized extreme pressure lubricant bases:

EXAMPLE I Two extreme pressure lubricant bases were prepared in accordance with United States Patents 2,211,231 and 2,211,306, supra. One of theextreme pressure lubricant bases was prepared from lard oil having its normal polyunsaturate glyceride content, ranging from 12 to 20 per- It is apparent from Table I that the extreme pressure lubricant base prepared from lard oil of reduced polyunsaturate glyceride content provides lubricant blends having the desired solubility and viscosity index characteristics.

The use of LPU lard oil as the fatty material in the preparation of extreme pressure lubricant additives can be further illustrated by the use of sulfurized LPU lard oil in cutting oil blends. Example II, below, describes the preparation of lubricants of this type.

EXAMPLE 11 Cutting oil concentrates were prepared by heating a mixture of 9.71 percent of a fatty material and one-half of the total mineral oil component (43.58 percent) to a temperature of 280 to 300 F. When the desired temperature was obtained, 2.80 percent of sulfur was added slowly with stirring. The temperature was then raised to 320 to 330 F. and maintained at this level for 4 to 4 hours. At the end of the reaction time, the sulfurized product was quenched with the remainder of the mineral oil (43.58 percent). The resulting cooled product was then stirred for one hour without additional heating and 0.03 percent of benzaldehyde was added as a deodorant. Table II, below, shows the characteristics of oil concentrates prepared in the manner described above using #1 lard oil of normal polyunsaturate glyceride content and LPU lard oil as the fatty materials and two difierent Mid-Continent mineral oils as the mineral oil component.

Table II Characteristics of finished blend Concentrate Fatty material Mineral 011 No. Grav- Flash Fire Pour Color Percent ity F. F. point NPA sulfur Storage stability (API) F.

1 9.71% #1 lard oil re- 87.49% solvent refined non- 32.6 405 460 +20 Black 2. 94 Separation (phase and maracted with 2.80% viscous neutral. bling) at room temp. in 1 sulfur. week. Heavy sulfur separation in 2 days at 32 F.

2 9.71% LPU lard 011 do 32.6 400 450 +5 8 2.77 Slight trace peppery sediment reacted with 2.80% in 30 days at room temp.; in sulfur. 30 days at 32 F. Minute trace sulfur crystals in 5 7 weeks at 32 F.

3 9.71% #1 lard oil re- 48.12% non-viscous solvent re- 27.0 375 430 +10 3.7 Heavy sulfur and polymer acted with 2.80% fined neutral. 39.37% 501- separation atroomtempand sulfur. vent extract from 100 visat 32 F. in 1 month.

cosity neutral.

4 9.71% LPU lard oil do 27-0 375 425 3.63 Slight polymer separation at reacted with 2.80% room temp. in 1 month. No sulfur. polymer separation at 32 F.

in 1 month.

It can be seen from Table II that the oil concentrates prepared from LPU lard oil were extremely stable in storage, while the concentrates prepared with lard oil of normal polyunsaturate glyceride content exhibited poor solubility characteristics as evidenced by their poor stability in storage.

The solubility and viscosity index characteristics of sulfurized-phosphorized lubricant bases can also be improved by substituting 40 to 60 percent of wool grease for fatty materials having normal polyunsaturate glyceride content. In Example III, below, extreme pressure lubricant bases were prepared from a fatty material having normal polyunsaturate glyceride content and from mixtures of wool grease and a fatty material having normal polyunsaturate glyceride content.

EXAMPLE III Two extreme pressure lubricant bases were prepared according to the method disclosed in United States Patents 2,211,231 and 2,211,306, supra. One extreme pressure lubricant base was prepared from lard oil having its normal polyunsaturate glyceride content. A second extreme pressure lubricant base was prepared from a mixture of 50 percent wool grease and 50 percent of lard oil having its normal polyunsaturate glyceride content. SAE 90 grade extreme pressure lubricant blends were prepared using 9 percent of BF. lubricant base, 1 percent of either dibenzyl disulfide or sulfurized terpene as the additional extreme pressure agent and 90' percent of lubricating mineral oil. The solubility characteristics of extreme pressure lubricant blends containing the two E.P. lubricant bases it has been found that the high polyunsaturate glyceride content of fatty materials can be effectively modified by preparing sulfurized-phosphorized lubricant bases in a manner such that the viscisity of the finished extreme pressure lubricant base is below about 400 SUS at 210 F. The viscosity of the sulfurized-phosphorized extreme pressure lubricant base is preferably between about 150 and 400 SUS at 210 F. rather than above about 450 SUS at 210 F. as are the extreme pressure lubricant bases heretofore used. The sulfurized and phosphorized extreme pressurelubricant bases having a viscosity below about 400 SUS at 210 F. can be prepared by carrying out the sulfurization and phosphorization at a temperature of about 300 to 350 F. while agitating with paddletype agitators at a speed of about 15 to revolutions per minute in an open or closed vessel. On the other hand, the preparation of lubricant bases in accordance with methods heretofore considered most desirable requires aeration of the heated reaction mixture by dispersing air in the mixture either with or without agitation to obtain a product having a viscosity above about 400 SUS at 210 F. The improvement in the solubility characteristics of extreme pressure lubricant bases attained by employing extreme pressure lubricant bases oflow viscosity is illustrated by Example IV, below.

EXAMPLE IV Two sulfurized-phosphorized extreme pressure lubricant bases were prepared in accordance with United States Patents 2,211,231 and 2,211,306, supra, using lard oil having its normal polyunsaturate glyceride content are shown in Table III, below. 40 of 12 to 20 percent. One extreme pressure lubricant Table III Blend Fatty oil used in E.P. base SAE grade blend composition 30-day storage stability 1 1? i d'iifiu 1 50% W00 grease 1 i enzy is e Light separation of E P additive at room temp 50 lard oil of 12 to 207 olyunsatu- 907 Mid-Continent solvent refined mineral oil 1 5m glyceride. p (33% MCSR bright stock) 27% m mosa Trace sepamlm addmve at neutral). 9% E.P. base 2 Lard oil of 12 to 20% polyunsaturate 1% dibenzyl disulfid Heavy separation of E.P. additive at room temp.

glyceride content. 90% Mid-Continent solvent refined ral 0 Heavy separation of E.P. additive at 32 F.

(61% 1120 MCSR oil) (29% 200 MOSR neutral). 9;, BasleE 3 50% Wool grease 1 S urize erpene Trace separation of E P additive at room temp 50 lard oil of 12 to 207 polyunsatu- 907 Mid-Continent solvent refined mineral oil 33 glyceflde 0 3 MOSH bright Stock) (35% MCSR h amt trace separation of 13.32. additive at 32 F.

neu ra It is to be observed that the lubricant blends containing wool grease-modified lard oil extreme pressure lubricant base were much more stable than the lubricant blend containing unmodified lard oil extreme pressure lubricant base.

Further, in accordance with the present invention,

base was prepared in a manner such that the viscosity of the finished base was 900 SUS at 210 F., while the other extreme pressure lubricant base was prepared in a manner such that the viscosity of the finished base was 276 SUS at 210 F. In this particular example the low viscosity extreme pressure lubricant base was prepared by agitating the reaction mixture in an open kettle at a paddle speed of about 15 revolutions per minute and the high viscosity base was prepared by introducing finely dispersed air into the reaction mixture. Extreme preshigher while destearinized fatty materials of reduced high melting point saturate glyceride content will exhibit a pour point below +50 F. Example V illustrates the advantages obtained by preparing extreme pressure lubrisure lubricant blends were prepared using 9 percent of cant bases from fatty materials of reduced high melting the extreme pressure lubricant base, 1 percent of dibenzyl point saturate glyceride content. disulfide or sulfurized terpene as the additional extreme pressure agent and 90 percent of mineral oil. The stor- EXAMPLE V age stabilities of the extreme pressure lubricant blends In a series of tests, 6 extreme pressure lubricant bases thus prepared are set forth in Table IV. were prepared according to United States Patents 2,211;

Table IV Bllend Description of E.P. base SAE 90 grade blend composition -day storage stability 1 Sulfurized-phosphoriaed lard oil E.P. 2% m: z' ggfi a' l'li:IZ II Heavy separation of E.P. base after storage at base hasving viscosity at 210 F. of 90% wt Mldcontment Solvent refined on (61% gctzggstglrgg Jig separation of E.P. base 9 yllflizltboin (29% 200 MCSR neutral).

W BS8 2 Sulinrized-phospborized lard oil E.P. 1% wt. sulfurized terpene No separation oi E.P. base after storage at room base having viscosity at 210 F. of 276 SUS.

90% wt. Mid-Continent solvent refined oil (58% 120 MCSR bright stock) (32% 200 MCSR neutral).

18% wt. E.P. base 1% wt. sullurized terpene 81% wt. Mid-Continent solvent refined oil (45% temp. N 0 separation of E.P. base after storage at 32 F.

No separation of E.P. base after storage at room temp. N 0 separation of E.P. base after storage neutral) at room temp.

Table IV effectively demonstrates that the extreme pressure lubricant blends containing the low viscosity extreme pressure lubricant base were highly stable and thus that this lubricant base was more compatible with high viscosity index mineral oil than was the high viscosity extreme pressure lubricant base.

It has also been found, in accordance with the present invention, that the low temperature characteristics of extreme pressure lubricant blends can be improved by employing sulfurized-phosphorized extreme pressure lubricant bases prepared from fatty materials of reduced high melting point saturate glyceride (also referred to as stearin) content. The high melting point saturate glyceride content is also preferably reduced by treating the fatty material in accordance with the Kellogg Solexol process of propanesolvent extraction. A convenient measure of the high melting point saturate glyceride content is the pour point of the fatty material. For example, a fatty material of normal saturate glyceride content will exhibit a pour point of about +50 F. or

231 and 2,211,306, supra. Table V, below, sets forth the characteristics of extreme pressure lubricant blends containing 18 percent of the extreme pressure lubricant base, 1 percent of sulfurized terpene as the additional extreme pressure agent and 81 percent of mineral oil. The extreme pressure lubricant bases used in lubricant blends la and lb of Table V were prepared from LPU lard oil of normal saturate glyceride content and LPU lard oil of reduced high melting point saturate glyceride content, respectively. The extreme pressure lubricant bases of lubricant blends 2a and 2b were prepared from wool grease-modified lard oil of normal saturate glyeeride content and wool grease-modified lard oil of reduced high melting point saturate glyceride content, respectively. And lubricant blends 3a and 3b contained extreme pressure lubricant bases of low viscosity prepared from lard oil of normal saturate glyceride content and lard oil of reduced high melting point saturate glyceride content, respectively.

Table V Blen Pour N 0. Fatty oil used in E.P. base SAE grade blend composition ppii t, 30-day storage stability 18% wt. E.P. base 1a Lard oil of 1 to 2% polyunsaturate glyceride 1% wt. suliurized terpene content and of ordinary steal-in" content and 81% wt. Mid-Continent solvent refined oil (31% +20 No separation of E.P. additive havingapour point of +50 F. MCSR bright stock) (50% 200 MCSR either at room temp. or at neutral). 32 F. 13% E R bage l w sn ur ze erpene 1b Lard oil of 5 to 6% polyunsaturate glyceride con- L O wt. Mid-Continent solvent refined oil (44% +10 Do. tent and destearinized to a put point of +40 F. 120 MCSR bright stock) (37% 200 MCSR neutral). 18% wt. E.P. base 2a 50% lard oil of 12 to 10% polyunsaturate glyceride 1% wt. suliurized terpene content and ordinary stearin" content and 81% wt. Mid-Continent solvent refined oil (44% L +35 having a pour point of +50 F. 50% wool grease. tMgSR. bright stock) (37% MCSR neu ra 18% wt. E.P. Base 2b 50% lard oil of 5 to 6% polyunsaturate glyceride 1% wt. sulturized terpene content and destearinized to a pour point of 81% wt. Mid-Continent solvent refined oil (41% +25 +40 F. 50% wool grease. 150 MCSR Bright Stock) (40% 170 MGSR Neutral). 18% wt. E.P. Base 3a Lard oil of 12 to 16% polyunsaturate glyceride 1% wt. sniiurized terpene content and ordinary "stearin" content and 81% wt. Mid-Continent solvent refined oil (44% +25 having a pour point of +50 F. 150 MgSR bright stock) (37% 170 MCSR neu 18% wt E.P. base 3b Lard oil of 5 to 6% polyunsaturate glyceride 1% wt suliurized terpe content and destearinized to a pour point of 81% wt. Mid-Continent sol d oil (40% +40 F. 150 tMSJSR. bright stock) (41% 170 MCBR neu ra 9 It is evident from the data'of Table thatfthe' lubricant blends containing extreme pressure lubricant bases prepared from fatty materials of reduced high-melting point saturate glyceride content have superior low tem- 10 they; also be added when necessary. Such odor-masking materials include pine oil and like materials which are well known in the art. In addition to the additives set forth above, other known lubricant compounding agents perature characteristics when compared with lubricant may be combined with the extreme pressure additives of blends containing extreme pressure lubricant bases prethls invention in the preparation of lubricating composipared from fatty materials of normal saturate glyceride trons. For example, gelling agents such as metallic soaps content. and finely divided inorganic solids may be added to form The characteristics of the mineral oils employed in the greases, lead soaps such as lead naphthenate and lead specific examples set forth above are listed in Table VI, sulfonate may be added to further increase the loadbelow. As has been pointed out above, the extreme carrying capacity, and emulsifying, agents, corrosion inpressure lubricant bases of this invention are universally hibitors and other known additives may be added to presoluble in mineral oils, and, therefore, mineral oils other pare a wide variety of lubricants. than those employed in the specific examples can be Any of the well known sulfurizing agents, such as sulutilized. It is generally conceded that solvent refined fur and sulfur chloride, and phosphorizing agents, such Mid-Continent mineral oils present the most severe probas phosphorous sulfides and phosphorous halides, may be lems relative to compatibility with additives, particularly employed in the preparation of the extreme pressure lubriextreme pressure lubricant additives. Thus, additives and cant additives of this invention. Suitable materials of bases which are soluble in Mid-Continent solvent refined this nature are set forth in United States Patents 2,211,- mineral oils will also be soluble in other mineral oils. 23.1, 2,211,306, supra, and related patent literature.

Table VI TYPICAL TESTS FOR MINERAL OILS API GOO GOO SUS at SUS at Viscos- Color, Percent Mineral oil gravity flash fire 100 F. 210 F. jay F. pour N PA sulfur 1I1 ex 15. 9 390 455 286 45. s 2 +50 36. 5 370 405 71. 35. 7 111 0 22.5 105 38.6 34 -40 17.8 515 590 5,530 151.6 -15 22.8 355 390 207.3 43.5 21 Below -30 150 Mid-Continent solvent refined bright stock 27. 2 555 615 2, 376 147 97 +6 170 Mid-Continent solvent refined neutral 30. 4 400 460 170. 5 44. 2 93 +20 200 Mid-Continent conv. refined neutral 25. 2 395 455 208.6 45. 3 70 +25 Non-viscous Mid-Continent solvent refined neutral. 36. 6 370 405 71. 3 36. 7 111 0 Extract from 100 Mid-Continent solvent refined neu 15. 9 390 455 286 45. 8 2 +50 1120 Mid-Continent solvent refined oil 24. 8 1, 623 118 98 +15 200 Mid-C ontinent solvent refined neutral 29. 7 410 470 201 46 91 +10 120 Mid-Continent solvent refined bright stock 25. 8 540 600 1, 985 125. 5 91 +15 The characteristics of the fatty materials employed in the specific examples of this specification are set forth in Table VII, below.

As has been indicated herein, suitable methods of sulfurizing or sulfurizing and phosphorizing fatty materials are set forth in detail in United States Patents Table VII TYPICAL TESTS FOR FATTY OILS Specific Flash, Fire, Pour Saponifi- Iodine Titer, Fatty material gravity F. F. point, cation number 0.

F. number #1 lard oil 0. 910-0. 915 430-450 480-510 -50 192198 70-73 3 LPU lard oil 201 09 Lard oil of 1 to 2% polyunsaturate and of ordinary stearin content +50 201 69 Lard oil of 5 to 6% polyunsaturate and destearinized to +40 F +40 200 75 Lard oil of 12 to 16% polyunsaturate content and ordinary stearin content +50 201 74 Although lard oil has been employed as the fatty material in the specific examples contained herein, other fatty materials which contain substantial amounts of polyunsaturate glycerides and/ or high melting point saturate glycerides can also be employed in the preparation of the extreme pressure lubricant additives and lubricants by following the teachings of the present invention. The term fatty material as employed in the specification and claims of this application is meant to include vegetable oils, animal fats and oils, and marine animal fats and oils. Typical examples of such fatty materials include sperm oil, hydrogenated soya oil, etc.

A suitable sulfurized terpene for use in the extreme pressure lubricant blends of this invention is the sulfurized terpene product prepared in accordance with United States Patent 2,443,823, issued to Lee Cone Holt on June 22, 1948. In addition to the sulfurized terpenes and dibenzyl disulfide set forth in the specific examples, other known extreme pressure agents may also be employed in the preparation of lubricant blends. Other deodorants than the benzaldehyde employed in Example II 2,211,231 and 2,211,306, supra. Briefly, sulfurized fatty materials may be prepared by heating the fatty material with sulfur or a compound of sulfur at a temperature below about 340 F. until the sulfur has reacted with the fatty material to form a product non-corrosive to a copper strip. Usually a reaction time of about 2 to 7 hours will be sufficient. A lubricant base containing chemically combined sulfur and phosphorous may be prepared by simultaneously sulfurizing and phosphorizing or by separately sulfurizing and then phosphorizing. In the former case, both sulfurizing and phosphorizing agents are mixed With the fatty material being treated and the mixture is heated to a temperature below about 450 F. for from 2 to 8 hours, preferably at a temperature of 425 to 450 F. for 2 /2 hours. In the method whereby sulfurization and phosphorization are carried out in separate steps, a sulfurized fatty material, prepared in the manner outlined above, is mixed with a phosphorizing agent and the mixture is heated to a temperature below about 280 F. for a period from about 1 to 5 hours. As is more fully disclosed in United States Patent 2,211,306, supra, phosphorization is preferably carried out at a temperature of about 210 to 230 F. until the reagents have reacted sufiiciently to prevent fuming of phosphorous when the temperature is raised above 230 F. (usually about hours). After the product has reached a point at which phosphorous will not fume, the temperature may be raised to a temperature not exceeding about 350 F. to produce a highly stable product.

It is obvious from a consideration of the data presented herein and the accompanying discussion thereof that extreme pressure lubricant bases, which are universally soluble in mineral oils and which when added to suitable mineral oils produce extreme pressure lubricants of improved viscosity index and low temperature characteristics, can be prepared by sulfurizing or sulfurizing and phosphorizing a mixture of wool grease and a fatty material of low polyunsaturate glyceride and high melting point glyceryl ester content under conditions such that a product having a viscosity below about 400 SUS at 210 F. is obtained.

Having described and illustrated the nature of this invention, what is claimed is:

1. The preparation of an extreme pressure lubricant additive having improved storage stability and low temperature characteristics when blended with solvent refined mineral lubricating oil from natural fattymaterial having a content of polyunsaturated glyceryl esters of high boiling fatty acids exceeding about 10%, which esters when chemically reacted with sulfur and phosphorus tend to form sulfur and phosphorus-containing reaction products insoluble in said lubricating oil, comprising reducing the content of said polyunsaturated glyceryl esters to about 1.0 to 2.0 weight percent, then sulfurizing and phosphorizing said material during mechanical agitation without blowing with an oxidizing medium under conditions of time and temperature such that a product having a viscosity below about 400 SUS at 210 F. is produced.

2. The method in accordance with claim 1 in which said natural fatty material is lard oil and the pour point of said lard oil is below about F. prior to said reactions.

References Cited in the file of this patent UNITED STATES PATENTS 

1. THE PREPARATION OF AN EXTREME PRESSURE LUBRICANT ADDITIVE HAVING IMPROVED STORAGE STABILITY AND LOW TEMPERTAURE CHARACTERISTICS WHEN BLENDED WITH SOLVENT REFINED MINERAL LUBRICATING OIL FROM NATURAL FATTY MATERIAL HAVING A CONTENT OF POLYUNSATURATED GLYCERYL ESTERS OF HIGH BOILING FATTY ACIDS EXCEEDING ABOUT 10%, WHICH ESTERS WHEN CHEMICALLY REACTED WITH SULFUR AND PHOSPHORUS TEND TO FORM SULFUR AND PHOSPHORUS-CONTAINING REACTION PRODUCTS INSOLUBLE IN SAID LUBRICATING OIL, COPRISING REDUCING THE CONTENT OF SAID POLYUNSATURATED GLYCERYL ESTER TO ABOUT 1.0 TO 2.0 WEIGHT PERCENT, THEN SULFURIZING AND PHOSPHORIZING SAID MATERIALDURING MECHANICAL AGITATION WITH OUT BLOWING WITH AN OXIDIZING MEDIUM UNDER CONDITIONS OF TIME AND TEMPERATURE SUCH THAT A PROCUCT HAVING A VISCOSITY BELOW ABOUT 400 SUS AT 210* F. IS PRODUCED. 